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GM introduces CNG bi-fuel Chevrolet Silverado and GMC Sierra pickups

Bi-fuel Chevrolet Silverado. Click to enlarge.

General Motors is introducing compressed natural gas (CNG) bi-fuel versions of the 2013 Chevrolet Silverado and GMC Sierra 2500 HD extended cab pickup trucks. Fleet and retail consumers can place orders beginning this April.

The vehicles feature a CNG-capable Vortec 6.0L V8 engine that seamlessly transitions between CNG and gasoline fuel systems. With both CNG and gasoline tanks full, the trucks offer a range of more than 650 miles. The Silverado and Sierra will be available in standard and long box, with either two- or four-wheel drive.

The Vortec engine features hardened exhaust valves and hardened intake and exhaust valve seats. Bosch supplies the fuel injection system. The trucks use a 17-gallon Type 3 CNG tank made from composite material with aluminum liner and carbon fiber wrap. GM placed a collar around the head of the tank for further safety.

Fuel tank and fuel door. Click to enlarge.

GM mounts the tank through the bed of the truck to the frame; the fuel door is high up and out of the impact area. All of the high pressure fuel lines run inside of the frame rails.

The trucks always start on gasoline, then switch over automatically to CNG after a few minutes once the appropriate temperature is reached. The trucks continue operating on CNG until the CNG tank is depleted, and then it automatically switches back to gasoline. The driver can switch from CNG to gasoline using a switch on the dashboard. An LED system on the switch monitors the fuel in the CNG tank.

Horsepower and torque are identical to the base truck when running on gasoline. On CNG there is “minimal” loss of horsepower and torque, according to GM. The bo-fuel truck offers comparable towing capability. The CNG system adds 450 lb. to the total weight of the truck.

GM is the only manufacturer to offer a single-source option for its gaseous fuel vehicles. The bi-fuel trucks are built with a specially designed engine, the fuel system is installed by GM’s Tier One supplier (IMPCO) and the completed vehicle is delivered directly to the customer. This process makes ordering the bi-fuel option as seamless and efficient as a standard vehicle.

The bi-fuel commercial trucks will be covered by GM’s three-year, 36,000-mile new vehicle limited warranty and five-year, 100,000-mile limited powertrain warranty and vehicle emissions warranty, meeting all Environmental Protection Agency (EPA) and California Air Resources Board (CARB) emission certification requirements.



2011 GMC 2500 HD owners are getting about 13 MPG for the 6.0 L V8 Version

2011 GMC 2500 HD gas version has 36 gallon tank

So 36 * 13 = 468

The article is saying range of Bifuel truck will be 650 miles, so range of 17 gallon CNG tank will be ~ 182 miles (650-468), or (182/17) 10.71 MPG...not a very good proposition UNLESS natgas is really, really cheap. Overall mileage will also be a little worse because of the 450 lb. natgas tank also.


I agree with what Henrik says that converting to room temperature liquid fuel is wasteful. I believe GTL has only about 55% of the thermal energy of the gas feedstock that went into each litre. I also believe that despite the efficiency of electric drive trains it is slightly less efficient overall to use the gas fired electricity->BEV route than using NGVs directly. You also have the range advantage of hundreds of kilometres on a 'fill up'.

The answer to the space taken up by pressure cylinders is for the standard car design to become a mini-van rather than a saloon. We could free up a lot of gas by not burning so much in power stations which is the job for nukes. In any case the price of NG might rise too high for industrial users like power stations.

The great thing about getting a petrol-CNG car is that even if there aren't many filling stations now they can build up over time as the petrol price escalates.


Another feature that hasn't been discussed is the ability to refuel the bifuel truck at home, like Boone Pickens does with his CNG Honda Civic. There's the potential, for one that does this, to only have to go to an actual gas station maybe every six months or so --- perhaps even less than that.


Out of perhaps 10 million pickup trucks very few are CNG. If GM and Dodge sell these trucks very few more will be CNG in the coming years. This is not the way to reduce OPEC oil imports in any significant way, whether new trucks or converted ones.

Even if it takes more than 2 therms of NG to make one gallon of gasoline, we have 100s of millions of vehicles that run on gasoline.

Expecting to change the world to suit our wants and expectations is not realistic. So expecting the world to all buy and drive CNG and EVs real soon now is not realistic.

So we take maybe 70 cents worth of natural gas to synthesize one gallon of gasoline versus $3 of oil to refine one gallon of gasoline. Now we use domestic natural gas instead of imported oil. Instead of sending $100 billion per year out of the country for imported oil, that money stays here to build our economy.


Aussie, you didn't figure the losses in the ICEV's engine.  When you burn NG in a CCGT at 60% efficiency, that is close to what's delivered to the wheels of a BEV.  The ICEV is closer to 35% efficient.

If we're aiming to get off imported petroleum, NGVs and nuclear beat GTL any day of the week.  GTL is just another way to preserve a market for liquid petroleum products.


In 1974 I ran into a Dude in the Gila Wilderness that was driving a Jeep (copy) built by Toyota that used Propane for fuel.

Wonder what happened to them?


Another idea would be to have a non-ICE NG vehicle, using a Bloom Energy solid-oxide fuel cell as the power plant. Any idea about the efficiency of a solid-oxide fuel cell vs. an NG powered ICE?


I support CNG, LNG, GTL and BEV. Let's do them all. None are perfect, all are better than gasoline.


EP with CCGT-->BEV I think you have to multiply two efficiencies. If that is 60% X 60% that works out at 36% combined from the starting thermal energy of the NG. My guess is that NGVs with piston engines, gear boxes and tail shafts can still get 36% of the combustion power to the wheels. As a bonus you get to drive hundreds of kilometres without needing to 'recharge'.

Dave R

BEV powered by CCGT efficiency:

CCGT = 60% efficiency
Transmission loss = 93% efficiency
Charging loss = 85% efficiency
Drivetrain loss = 90% efficiency

Total efficiency = 43%

Tough to beat unless you have a hybrid drivetrain.

Or to look at it another way:

CCGT plants emit about 340-400 g CO2 / kWh - let's assume upper end which is 400 g CO2/kWh.

Nissan LEAF is rated 340 Wh / mi by the EPA - or about 140 g CO2/mi.

The CNG Civic is rated 36 mpg hwy - which the EPA says emits about 196 g CO2/mi.

So the CCGT powered LEAF is 30% more efficient than the CNG Civic on the highway - and about 50% more efficient in the city.

Save the natural gas for long-haul driving where range is an issue - use electricity for everything else.


A plug-in E-REV with the range extender fueled by NG?


Picken's company is installing LNG fueling at truck stops around the U.S. Once big rig operators find out how much they can save in fuel, it could be popular.

We could convert local delivery trucks to CNG, they could save money and the air would be cleaner. Lots of moves we could make, but will we do it in large numbers soon enough to make a difference?


"...according to government and industry data there are no more than about 150,000 CNG-powered vehicles on U.S. roads right now, a pittance compared to the 2.7 million in use in Pakistan, which has the global lead, according to the International Association for Natural Gas Vehicles. Iran follows, with 1.95 million as of 2011, with Argentina close behind with 1.9 million vehicles running on CNG."


From wikipedia: "Worldwide, there were 12.7 million natural gas vehicles by 2010, led by Pakistan with 2.7 million, Iran (1.95 million), Argentina (1.9 million), Brazil (1.7 million), and India (1.1 million).

The Asia-Pacific region leads the world with 6.8 million NGVs, followed by Latin America with 4.2 million vehicles."


The key isn't what we've got now, it's what we can build.  If Pakistan can be the world leader in NGVs, it's not something that takes a big technical advance.


Some googling suggests that the well-to-wheels efficiency of internal combustion engines will always be under 20% compared to 40% or so for BEVs powered by electricity from the same fossil fuel. Therefore I was wrong upthread saying they could be comparable.

A simple fix for that could be to double the number of vehicle occupants. The point being that we're going to have to change from happy motoring to less happy motoring. We'll have to put up with more cost, fewer trips, less range, slower filling or recharge times, slower speeds, higher occupancy rules or some combination of these restrictions.


Robert Brogden Buick GMC in Kansas City has Sierra trucks for sale AND a blog that discusses the model's different features:

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